A molten salt flue gas heat exchange system

Abstract

This application discloses a molten salt flue gas heat exchange system, belonging to the field of flue gas waste heat utilization technology. It includes a shell, with an upper end cap fixedly connected to the top of the shell, a feed pipe fixedly connected to the top of the upper end cap, a storage hopper fixedly connected to the top of the feed pipe, a lower end cap fixedly connected to the bottom of the shell, and a discharge pipe fixedly installed at the bottom of the lower end cap. An electrically controlled valve is fixedly installed inside the feed pipe, and a controller is fixedly installed at the top of the storage hopper. Several sets of heat exchange tubes are arranged inside the shell. An inlet pipe is fixedly installed on one side of the shell, and an exhaust pipe is fixedly installed at the bottom of the shell. The application uses a temperature sensor to detect a lower temperature, which reduces the opening degree of the electrically controlled valve in the feed pipe, thereby controlling the flow rate of molten salt falling from the storage hopper into the upper end cap. This achieves the purpose of controlling the flow rate of molten salt inside the shell, facilitating sufficient heat exchange between the flue gas and the molten salt and heat exchange tubes, and improving the stability of the system operation.

Description

Technical Field

[0001] This application relates to the field of flue gas waste heat utilization technology, and in particular to a molten salt flue gas heat exchange system. Background Technology

[0002] In the steel production process, blast furnace gas is a byproduct produced during blast furnace ironmaking. Its main components include carbon monoxide, carbon dioxide, nitrogen, and a small amount of hydrogen. Blast furnace gas has a high calorific value. Molten salt energy storage technology is considered an effective way to store and utilize waste heat due to its high energy density and good thermal stability. Molten salt energy storage systems can convert the waste heat of blast furnace gas into thermal energy and store it, and then release the thermal energy for power generation or heating when needed.

[0003] Most existing molten salt energy storage systems lack a complete automated control system, making it impossible to monitor and adjust the system's operating parameters in real time. Operators need to manually adjust parameters such as flue gas flow and molten salt flow, making it difficult to make precise control according to actual working conditions. This results in unstable system operation and unsatisfactory waste heat recovery.

[0004] Therefore, this application provides a molten salt flue gas heat exchange system. Utility Model Content

[0005] To address the shortcomings of existing technologies, this application provides a molten salt flue gas heat exchange system, which overcomes the deficiencies of existing technologies. It aims to solve the problem that most existing molten salt energy storage systems lack a complete automated control system, making it impossible to monitor and adjust the system's operating parameters in real time. Operators need to manually adjust parameters such as flue gas flow and molten salt flow, making it difficult to accurately control according to actual working conditions, resulting in unstable system operation and unsatisfactory waste heat recovery.

[0006] To achieve the above objectives, this application provides the following technical solution: a molten salt flue gas heat exchange system, comprising a shell, an upper end cap fixedly connected to the top of the shell, a feed pipe fixedly connected to the top of the upper end cap, a storage hopper fixedly connected to the top of the feed pipe, a lower end cap fixedly connected to the bottom of the shell, a discharge pipe fixedly installed at the bottom of the lower end cap, an electrically controlled valve fixedly installed inside the feed pipe, a controller fixedly installed at the top of the storage hopper, several sets of heat exchange tubes arranged inside the shell, a flue gas inlet pipe fixedly installed on one side of the shell, a flue gas exhaust pipe fixedly installed at the bottom of the shell, a temperature sensor three fixedly installed inside the discharge pipe, and both the temperature sensor three and the electrically controlled valve being electrically connected to the controller.

[0007] By adopting the above technical solution, blast furnace gas enters the heat exchanger shell from the flue gas inlet pipe and exchanges heat with the molten salt in the heat exchange tubes, causing the molten salt temperature to rise and the blast furnace gas temperature to drop. Temperature sensor three monitors the molten salt temperature at the discharge pipe in real time and feeds the monitored data back to the controller. The controller automatically adjusts the opening degree of the electric control valve in the discharge pipe according to the preset program. The lower the temperature detected by temperature sensor three, the smaller the opening degree of the electric control valve in the discharge pipe, thereby controlling the flow rate of molten salt falling from the storage hopper into the upper head, achieving the purpose of controlling the flow rate of molten salt in the shell. This is conducive to sufficient heat exchange between the flue gas, molten salt and heat exchange tubes, improving the stability and reliability of the system operation and enhancing the waste heat recovery effect.

[0008] As a preferred technical solution of this application, a filter mechanism is provided at the end of the smoke inlet pipe away from the housing. The filter mechanism includes a filter tube, one end of which is installed at one end of the smoke inlet pipe. A filter layer is installed inside the filter tube, and a purification layer is installed inside the filter tube. The purification layer is located between the filter layer and the smoke inlet pipe.

[0009] By adopting the above technical solution, before the blast furnace gas enters the flue gas pipe, it first passes through the filter layer in the filter pipe to preliminarily filter the particles and impurities in the flue gas. Then, the purification layer filters the flue gas containing corrosive gases or particles, allowing the clean gas to enter the shell and exchange heat with the molten salt in the heat exchange tube. This effectively reduces the corrosion and blockage of the heat exchange tube and lowers the maintenance requirements of the heat exchange tube.

[0010] As a preferred technical solution of this application, an upper tube sheet and a lower tube sheet are fixedly installed inside the shell. The upper tube sheet and the lower tube sheet are distributed vertically, and several sets of heat exchange tubes are inserted inside the upper tube sheet and the top of the several sets of heat exchange tubes passes through the upper tube sheet, and the bottom of the several sets of heat exchange tubes passes through the lower tube sheet.

[0011] By adopting the above technical solution, several sets of heat exchange tubes are stably fixed inside the shell through the upper tube sheet and the lower tube sheet, and the heat exchange area is effectively increased by using several sets of heat exchange tubes, thereby improving the heat exchange efficiency between flue gas and molten salt.

[0012] As a preferred technical solution of this application, a temperature sensor 1 is fixedly installed inside the smoke inlet pipe, and a temperature sensor 2 is fixedly installed in the middle of the smoke exhaust pipe. Both the temperature sensor 1 and the temperature sensor 2 are electrically connected to the controller.

[0013] By adopting the above technical solution, the temperature of the flue gas in the inlet pipe is monitored in real time by temperature sensor one, and the temperature of the flue gas in the exhaust pipe is monitored in real time by temperature sensor two. Temperature sensors one and two feed back the monitored data to the controller. The controller automatically adjusts the opening degree of the electric control valve in the feed pipe according to the preset program, thereby controlling the flow rate of molten salt, which is conducive to sufficient heat exchange between flue gas and molten salt and heat exchange tube.

[0014] As a preferred technical solution of this application, sealing rings are fixedly installed at the connection points between the upper tube sheet and the lower tube sheet and the housing.

[0015] By adopting the above technical solution, the tightness of the connection between the upper and lower tube sheets and the shell is improved by using sealing rings, which avoids energy waste and environmental pollution caused by flue gas leakage and improves heat exchange efficiency.

[0016] As a preferred technical solution of this application, a connecting pipe is fixedly installed at the top of the shell, and the connecting pipe is connected to the storage hopper.

[0017] By adopting the above technical solution, the connection pipe facilitates the replenishment of low-temperature molten salt into the storage hopper, ensuring the continuity of the heat exchange process.

[0018] As a preferred technical solution of this application, a flow sensor is fixedly installed in the middle of the feed pipe, and a pressure sensor is fixedly installed in the middle of the smoke inlet pipe. Both the flow sensor and the pressure sensor are electrically connected to the controller.

[0019] By adopting the above technical solution, the flow rate of molten salt in the feed pipe is monitored in real time by a flow sensor, and the pressure sensor monitors the flue gas pressure in the flue gas inlet pipe in real time and feeds it back to the controller, thereby improving the safety during use.

[0020] As a preferred technical solution of this application, the outer surface of the shell is covered with a heat insulation layer, and the heat exchange tube is made of a special alloy.

[0021] By adopting the above technical solution, the heat loss of the shell is reduced through the insulation layer, the overall thermal efficiency is improved, and the heat exchange tube is made of special alloy, which has the characteristics of high temperature resistance and corrosion resistance, thus extending the service life of the heat exchange tube and facilitating long-term stable operation.

[0022] The beneficial effects of this application are:

[0023] 1. Blast furnace gas enters the heat exchanger shell through the flue gas inlet pipe and exchanges heat with the molten salt in the heat exchange tubes, causing the molten salt temperature to rise and the blast furnace gas temperature to drop. Temperature sensor three monitors the molten salt temperature at the discharge pipe in real time and feeds the monitored data back to the controller. The controller automatically adjusts the opening degree of the electric control valve in the discharge pipe according to the preset program. The lower the temperature detected by temperature sensor three, the smaller the opening degree of the electric control valve in the discharge pipe, thereby controlling the flow rate of molten salt falling from the storage hopper into the upper head. This achieves the purpose of controlling the flow rate of molten salt in the shell, which is conducive to sufficient heat exchange between the flue gas, molten salt and heat exchange tubes, and improves the stability of system operation.

[0024] 2. Before the blast furnace gas enters the flue gas inlet pipe, it first passes through the filter layer in the filter pipe to preliminarily filter the particles and impurities in the flue gas. Then, the purification layer filters the flue gas containing corrosive gases or particulate matter, allowing the clean gas to enter the shell and exchange heat with the molten salt in the heat exchange tube. This effectively reduces the corrosion and blockage of the heat exchange tube and lowers the maintenance requirements of the heat exchange tube. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of this application;

[0026] Figure 2 This is a partial cross-sectional structural diagram of this application;

[0027] Figure 3 for Figure 2 Enlarged structural diagram at point A in the middle;

[0028] Figure 4 This is a schematic diagram of the filtration mechanism.

[0029] In the diagram: 1. Shell; 2. Upper end cap; 3. Feed pipe; 4. Storage hopper; 5. Lower end cap; 6. Discharge pipe; 7. Controller; 8. Upper tube sheet; 9. Lower tube sheet; 10. Heat exchange tube; 11. Flue gas inlet pipe; 12. Flue gas outlet pipe; 13. Temperature sensor one; 14. Pressure sensor one; 15. Temperature sensor two; 16. Filtration mechanism; 1601. Filter tube; 1602. Filter layer; 1603. Purification layer; 17. Connecting pipe; 18. Temperature sensor three; 19. Flow sensor; 20. Insulation layer; 21. Sealing ring. Detailed Implementation

[0030] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0031] Reference Figure 1-4 A molten salt flue gas heat exchange system includes a shell 1, an upper end cap 2 fixedly connected to the top of the shell 1, a feed pipe 3 fixedly connected to the top of the upper end cap 2, a storage hopper 4 fixedly connected to the top of the feed pipe 3, a lower end cap 5 fixedly connected to the bottom of the shell 1, a discharge pipe 6 fixedly installed at the bottom of the lower end cap 5, an electrically controlled valve fixedly installed inside the feed pipe 3, a controller 7 fixedly installed at the top of the storage hopper 4, several sets of heat exchange tubes 10 arranged inside the shell 1, and a flue gas inlet fixedly installed on one side of the shell 1. A flue pipe 12 is fixedly installed at the bottom of the casing 1. A temperature sensor 3 18 is fixedly installed inside the discharge pipe 6. The temperature sensor 3 18 and the electric control valve are electrically connected to the controller 7. An upper tube sheet 8 and a lower tube sheet 9 are fixedly installed inside the casing 1. The upper tube sheet 8 and the lower tube sheet 9 are distributed vertically. Several sets of heat exchange tubes 10 are inserted inside the upper tube sheet 8 and the lower tube sheet 9. The top of the several sets of heat exchange tubes 10 passes through the upper tube sheet 8, and the bottom of the several sets of heat exchange tubes 10 passes through the lower tube sheet 9.

[0032] Blast furnace gas enters the heat exchanger shell 1 through the flue gas inlet pipe 11 and exchanges heat with the molten salt in the heat exchange tubes 10, causing the molten salt temperature to rise and the blast furnace gas temperature to drop. The temperature of the molten salt at the discharge pipe 6 is monitored in real time by temperature sensor 3 18, and the monitored data is fed back to the controller 7. The controller 7 automatically adjusts the opening degree of the electric control valve in the discharge pipe 3 according to the preset program. The lower the temperature detected by temperature sensor 3 18, the smaller the opening degree of the electric control valve in the discharge pipe 3, thereby controlling the flow rate of molten salt falling from the storage hopper 4 into the upper head 2, achieving the purpose of controlling the flow rate of molten salt in the shell 1. This is conducive to sufficient heat exchange between the flue gas and the molten salt and the heat exchange tubes 10, and improves the stability of system operation. Several sets of heat exchange tubes 10 are stably fixed inside the shell 1 by the upper tube plate 8 and the lower tube plate 9, and the use of several sets of heat exchange tubes 10 effectively increases the heat exchange area and improves the heat exchange efficiency between the flue gas and the molten salt.

[0033] Reference Figure 2-4 A filter mechanism 16 is provided at the end of the smoke inlet pipe 11 away from the housing 1. The filter mechanism 16 includes a filter tube 1601, one end of which is installed at one end of the smoke inlet pipe 11. A filter layer 1602 is installed inside the filter tube 1601, and a purification layer 1603 is installed inside the filter tube 1601. The purification layer 1603 is located between the filter layer 1602 and the smoke inlet pipe 11. A temperature sensor 13 is fixedly installed inside the smoke inlet pipe 11, and a temperature sensor 15 is fixedly installed in the middle of the exhaust pipe 12. Both the temperature sensor 13 and the temperature sensor 15 are electrically connected to the controller 7.

[0034] Before the blast furnace gas enters the flue gas inlet pipe 11, it first passes through the filter layer 1602 in the filter pipe 1601 to preliminarily filter the particles and impurities in the flue gas. Then, the purification layer 1603 filters the flue gas containing corrosive gases or particulate matter, allowing the clean gas to enter the shell 1 and exchange heat with the molten salt in the heat exchange tube 10. This effectively reduces the corrosion and blockage of the heat exchange tube 10 and lowers the maintenance requirements of the heat exchange tube 10. The temperature of the flue gas in the inlet pipe 11 is monitored in real time by temperature sensor 13, and the temperature of the flue gas in the exhaust pipe 12 is monitored in real time by temperature sensor 25. The temperature sensors 13 and 25 feed the monitored data back to the controller 7. The controller 7 automatically adjusts the opening degree of the electric control valve in the feed pipe 3 according to the preset program, thereby controlling the flow rate of molten salt, which is conducive to sufficient heat exchange between the flue gas and the molten salt and the heat exchange tube 10.

[0035] Reference Figure 1-3 Both the upper tube sheet 8 and the lower tube sheet 9 are fixedly installed with sealing rings 21 at their connections to the housing 1; a flow sensor 19 is fixedly installed in the middle of the feed pipe 3, and a pressure sensor 14 is fixedly installed in the middle of the flue gas inlet pipe 11. Both the flow sensor 19 and the pressure sensor 14 are electrically connected to the controller 7. The sealing rings 21 improve the tightness of the connection between the upper tube sheet 8 and the lower tube sheet 9 and the housing 1, avoiding energy waste and environmental pollution caused by flue gas leakage and improving heat exchange efficiency. The flow sensor 19 monitors the flow rate of molten salt in the feed pipe 3 in real time, and the pressure sensor 14 monitors the flue gas pressure in the flue gas inlet pipe 11 in real time and feeds it back to the controller 7, improving safety during use.

[0036] Reference Figure 1-3 A connecting pipe 17 is fixedly installed at the top of the shell 1, and the connecting pipe 17 is connected to the storage hopper 4; the outer surface of the shell 1 is covered with a heat insulation layer 20, and the heat exchange tube 10 is made of a special alloy; the connecting pipe 17 facilitates the replenishment of low-temperature molten salt into the storage hopper 4, ensuring the continuity of the heat exchange process; the heat insulation layer 20 reduces the heat loss of the shell 1 and improves the overall thermal efficiency, and the heat exchange tube 10 is made of a special alloy, which has the characteristics of high temperature resistance and corrosion resistance, extending the service life of the heat exchange tube 10 and facilitating long-term stable operation.

[0037] Working principle: Blast furnace gas enters the heat exchanger shell 1 from the flue gas inlet pipe 11, where it exchanges heat with the molten salt in the heat exchange tube 10, causing the molten salt temperature to rise and the blast furnace gas temperature to drop. Temperature sensor 3 18 monitors the molten salt temperature at the discharge pipe 6 in real time and feeds the data back to the controller 7. The controller 7 automatically adjusts the opening degree of the electrically controlled valve in the discharge pipe 3 according to a preset program. The lower the temperature detected by temperature sensor 3 18, the smaller the opening degree of the electrically controlled valve in the discharge pipe 3, thereby controlling the flow rate of molten salt falling from the storage hopper 4 into the upper head 2, achieving temperature control. The purpose of controlling the molten salt flow rate inside the shell 1 is to facilitate sufficient heat exchange between the flue gas and the molten salt and heat exchange tube 10, thereby improving the stability of the system operation. Before the blast furnace gas enters the flue gas inlet pipe 11, it first passes through the filter layer 1602 in the filter pipe 1601 to preliminarily filter the particles and impurities in the flue gas. Then, the purification layer 1603 filters the flue gas containing corrosive gases or particulate matter, allowing clean gas to enter the shell 1 and exchange heat with the molten salt in the heat exchange tube 10. This effectively reduces the corrosion and blockage of the heat exchange tube 10 and reduces the maintenance requirements of the heat exchange tube 10.

[0038] Several sets of heat exchange tubes 10 are stably fixed inside the shell 1 by the upper tube sheet 8 and the lower tube sheet 9. The heat exchange area is effectively increased by the use of several sets of heat exchange tubes 10, which improves the heat exchange efficiency between flue gas and molten salt. The flue gas temperature in the flue gas inlet pipe 11 is monitored in real time by temperature sensor 13, and the flue gas temperature in the flue gas outlet pipe 12 is monitored in real time by temperature sensor 25. The temperature sensors 13 and 25 feed back the monitored data to the controller 7. The controller 7 automatically adjusts the opening degree of the electric control valve in the feed pipe 3 according to the preset program, thereby controlling the flow rate of molten salt, which is conducive to sufficient heat exchange between flue gas, molten salt and heat exchange tubes 10.

[0039] Meanwhile, the sealing ring 21 improves the tightness of the connection between the upper tube sheet 8 and the lower tube sheet 9 and the shell 1, avoiding energy waste and environmental pollution caused by flue gas leakage and improving heat exchange efficiency; the connecting pipe 17 facilitates the replenishment of low-temperature molten salt into the storage hopper 4, ensuring the continuity of the heat exchange process.

[0040] In addition, the flow rate of molten salt in the feed pipe 3 is monitored in real time by the flow sensor 19, and the pressure sensor 14 monitors the flue gas pressure in the flue gas inlet pipe 11 in real time and feeds it back to the controller 7, which improves the safety during use. The heat loss of the shell 1 is reduced by the insulation layer 20, which improves the overall thermal efficiency. The heat exchange tube 10 is made of a special alloy, which has the characteristics of high temperature resistance and corrosion resistance, which extends the service life of the heat exchange tube 10 and is conducive to long-term stable operation.

[0041] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A molten salt flue gas heat exchange system, comprising a shell (1), characterized in that, The top of the shell (1) is fixedly connected to an upper end cap (2), the top of the upper end cap (2) is fixedly connected to a feed pipe (3), the top of the feed pipe (3) is fixedly connected to a storage hopper (4), the bottom of the shell (1) is fixedly connected to a lower end cap (5), the bottom of the lower end cap (5) is fixedly installed with a discharge pipe (6), the inside of the feed pipe (3) is fixedly installed with an electric control valve, the top of the storage hopper (4) is fixedly installed with a controller (7), the inside of the shell (1) is provided with several sets of heat exchange tubes (10), the side of the shell (1) is fixedly installed with a smoke inlet pipe (11), the bottom of the shell (1) is fixedly installed with a smoke exhaust pipe (12), the inside of the discharge pipe (6) is fixedly installed with a temperature sensor (18), the temperature sensor (18) and the electric control valve are both electrically connected to the controller (7).

2. The molten salt flue gas heat exchange system according to claim 1, characterized in that, A filter mechanism (16) is provided at one end of the smoke inlet pipe (11) away from the housing (1). The filter mechanism (16) includes a filter tube (1601), one end of which is installed at one end of the smoke inlet pipe (11). A filter layer (1602) is installed inside the filter tube (1601), and a purification layer (1603) is installed inside the filter tube (1601). The purification layer (1603) is located between the filter layer (1602) and the smoke inlet pipe (11).

3. The molten salt flue gas heat exchange system according to claim 1, characterized in that, The upper tube sheet (8) and the lower tube sheet (9) are fixedly installed inside the shell (1). The upper tube sheet (8) and the lower tube sheet (9) are distributed vertically, and several sets of heat exchange tubes (10) are inserted inside the upper tube sheet (8) and the lower tube sheet (9). The top of the several sets of heat exchange tubes (10) is provided through the upper tube sheet (8), and the bottom of the several sets of heat exchange tubes (10) is provided through the lower tube sheet (9).

4. The molten salt flue gas heat exchange system according to claim 1, characterized in that, Temperature sensor 1 (13) is fixedly installed inside the smoke inlet pipe (11), and temperature sensor 2 (15) is fixedly installed in the middle of the smoke outlet pipe (12). Temperature sensor 1 (13) and temperature sensor 2 (15) are both electrically connected to the controller (7).

5. The molten salt flue gas heat exchange system according to claim 3, characterized in that, Both the upper tube sheet (8) and the lower tube sheet (9) are fixedly installed with sealing rings (21) at the connection points with the housing (1).

6. The molten salt flue gas heat exchange system according to claim 1, characterized in that, A connecting pipe (17) is fixedly installed at the top of the shell (1), and the connecting pipe (17) is connected to the storage hopper (4).

7. The molten salt flue gas heat exchange system according to claim 1, characterized in that, A flow sensor (19) is fixedly installed in the middle of the feed pipe (3), and a pressure sensor (14) is fixedly installed in the middle of the smoke inlet pipe (11). Both the flow sensor (19) and the pressure sensor (14) are electrically connected to the controller (7).

8. The molten salt flue gas heat exchange system according to claim 1, characterized in that, The outer surface of the shell (1) is covered with a heat insulation layer (20), and the heat exchange tube (10) is made of a special alloy.

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